macbookpro4,1 upgrade os x from snow leopard compatibility with iPhone 5S

I've been meaning to upgrade the OS X on my Oct 2008 macbookpro4,1 - 2.4 GHz - 2GB RAM forever. I just purchased an iPhone 5S and dont want to get ahead of myself.

Three (maybe Four) inter-related questions:

1. 
   

   What is highest OS X upgrade to run smoothly on my macbookpro4,1? It is still running os x 10.6.8. and I just loaded iTunes 11.1.1 and I'm still able to backup the new iPhone 5S running iOS 7.1.1 directly to computer.

   
   


2. 
   

   what is highest pairing of OS X AND ios AND version of iTunes, that will run smoothly on my computer and still allow me to backup my iPhone to the computer?

   
   


3. 
   

   If I upgrade phone to iOS 8.1.1 will I need to upgrade iTunes to ver. 12 and will it run on OS X 10.7... or will I need to upgrade to 10.8? I thought I saw somewhere that 10.7 was highest OS X to run on my macbookpro4,1???

   
   

Cheers